No experience at LGA, but I have been into BOS, EWR, and TEB on numerous occasions for Angel Flight. I have had no issues per se, but I say that with the caveat of the being on an active IFR flight plan each time. Should be no problem, but you can expect to get numerous vectors, so a sterile cockpit is a must as the instructions can come rapid fire. I have heard on the radio controllers "kick out" VFR pilots from Class B airspace due to delay in response and/or numerous attempts to get the instructions correct. They will also quickly chastise you if the assigned heading/altitude is not maintained. I believe the key is good radio phraseology and good attention to detail.
